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AD30R intermittent power loss

Posted: Thu Sep 17, 2009 5:27 am
by joeereid
Maybe someone can relate to this problem before I ship this thing off to Orange for a rebuild. I have an AD30R that I bought new when they first came out. About a year ago it started "powering off" randomly while playing thru it. What happens is the power light will go off for a second or more and then light back up. I thought it was just the bulb connection but it wasn't. The tubes were actually losing power like the amp had been turned off. Sometimes it will be off for only a second so you wouldn't hear the amp "fading" and other times it will stay out long enough for the amp to fade out and then it comes back on and the amp comes back to life. The tech at OrangeUSA suggested hard-wiring the heater supply wires. which we did, but the problem remains. I have tried several sets of tubes [EL84 & 12ax7] both new and used, swapped with[working] tubes from a VOXac30 and Crate Vintage Club 30 and the problem is still there. I thought I had it fixed last week when I swapped out the tubes again after a couple of techs I know were sure it was a tube issue. I got 1.5 hours of use out of it last week with no problems and then just as I reached to hit the standby switch tonight the light went off and then back on again. I doesn't seem to matter if the amp is cold or if it's been running for hours. I have not been swapping the rectifier but we tried it with a different rectifier a while back and that didn't solve the problem. I've tried banging on the amp, wiggling the power cord, cooling it, heating it, volume up/down, hi-gain, knob sweep guitar plugged/un-plugged etc. and cannot seem to replicate the problem 'on demand'. Anybody have any idea what the problem may be?
About 4 years ago a tube shorted and took out the output transformer and burned a hole in the board The tech I took it to put a trans from an Ampeg in it . It lost a little of it's "chime" but worked and sounded fine. I've been struggling with this problem for a year and am getting ready to ship it to Orange and see if they can figure it out. I don't want to send it to a bunch of local [Seattle] techs and pay bench rate to to have them say they can't duplicate the problem. I can have Orange put in a new stock trans. and fix the hole burned in the board from when it blew. That is of course unless someone here knows what the problem is.